1. Field of the Invention
The invention relates to electronic circuits, and more particularly, to a calibration device and related methods for a phase difference between data signal and clock signal.
2. Description of the Related Art
A following situation may arise in signal transmission. A data signal and a clock signal of the same frequency are emitted by a transmitter, and a phase difference between them is 0.5π (i.e. a phase difference of 90 degrees). Thus, the clock signal edge is aligned with the center of the data signal as shown in FIG. 1A, and there are no errors when a receiver samples the data signal via the clock signal. However, the phase difference of the data signal and the clock signal appearing at the receiver may be not 0.5π (for example, as shown in FIGS. 1B and 1C) due to various causes. If the clock signal edge is close to the data signal edge, there may be a sampling error. Therefore, a device and a method are needed to calibrate the phase difference between the data signal and the clock signal at 0.5π, thereby assisting in reducing probability of sampling data signal incorrectly.
Conventional techniques can not correctly sample the data signal because a frequency variation between the clock signal and the data signal is large. Therefore, an effective device and an effective method are needed to calibrate the phase difference between the data signal and the clock signal at 0.5π, and to be suitable for phase calibration for the data signal and the clock signal within a large frequency band.